How to work with disengaged coworkers?

If you have to stay at that company (for whatever reasons), it'll take time or it even may be impossible.

I once myself was in a "disengaged" state :-) What motivated me most was a co-worker, that just MADE STUFF HAPPEN, I never thought was possible by just doing it.

"Migration from svn to git? Impossible with this codebase and deployment strategy" everyone thought. He made it happen by tinkering around with tools and somehow he got it working.

"Establishing a CI? No way that is possible within our worktime"... He invested some time and made it happen.

"Code Reviews? Who needs that?" He convinced us to try it out and it was the best and most wanted Meeting we had in our whole week.

So, maybe you could try to be that guy. Make things happen, don't try to point your finger on others, just pick a problem everybody has and try to solve it. It may not work, but at least you learn something on your way. But prepare to have stamina, it needs time (about a year).

Your disengaged coworker has it right.

Remind yourself what salaried positions are for: collecting a paycheck so you can take care of your you and your family. They're not for meaning, or purpose, or motivation, unless you have serious equity.

Remind yourself that you're not your job.

Find a new gig.